Increasing numbers of vehicles have an electrical motor driven, mechanical or pneumatic, multiple support adjustment seats with a controller system offering optional upscale features. Vehicle is herein construed as including car, truck, rail train, airplane, and the like. The features may include multiple displacements of several seat portions and incorporation of a seat lumbar support. In addition, a position sensor and a memory module for closed loop feedback positioning of various supports in the seat relative to the user seat position is selected by the user or automatically set by controller module memory settings. For example, this allows a person, identified as and with a controller # one, to various seat adjustment positions to an individual preference, and then set memory # one for these settings. When the recall position # one switch actuator is manipulated, for example, a recall button is pressed, the seat will return to the multiple adjusted preference settings set by driver # one.
Likewise, person # two may set memory # two and recall position # two, if the system is designed for additional personal settings. The basic seat lumbar adjustment control offers no lumbar position sensor. The optional system upgrade version typically includes a modular controller having the seat position memory feature which necessarily includes a seat position sensor system.
However, these previously known seating systems require sensor systems for precise displacement and positioning of the seat portions, and each movement may require its own set of input switches, limit switches, sensors or the like, as well as power supply for the sensors and the sensor responsive equipment. Such components can add a substantial amount of hardware, complexity and cost to the system and increase the size of the system and the time and the cost of production.
Although some previously known motor control systems have recognized that commutator pulses may be used to gauge motor rotation speed, such systems have not been readily applicable to seat assemblies. Motor brush or other dust may interfere with the detection of pulses, and may create false pulses. In addition, in-rush current at motor start-up and initial movement may interfere with detection of pulses that should have occurred. As a result, previously known pulse counting applications did not accurately gauge positioning of the components moved by a motor, or permit repeatability of positioning, for example in a seat mechanism, involving starting and stopping over time. As a result, separate sensor systems have been relied upon to control positioning.
Stepper motor controllers have been utilized by the machine industry for some time. An example would be indexing to position to place a part or remove a part. In addition, there is usually a feedback sensor as a redundant to verify the accuracy. However, these systems are far too expensive for adaptation to automotive implementation such as seating control features.
As a result, traditional seat control systems have grown in size, weight, complexity and cost due to increasing consumer demand for new features.